1. Field of the Invention
The present invention relates to a failure recovery system, and a method of creating the failure recovery system, and more particularly to a technique for reducing the amount of resources used for a redundant configuration, and reducing a failure recovery time in the redundant configuration equipped with a virtual server which is a switching destination when a common failure occurs in plural virtual servers providing a communication service.
2. Description of the Background Art
With the spread of cloud computing, data centers provided by data center providers or communication carriers are increasingly used. In general, the data centers are frequently installed at remote locations, and accessed via a local area network (LAN) or a wide area network (WAN) in use.
In the network using the WAN, a communication speed becomes low because a line quality is low as compared with the network using the LAN. Under the circumstances, in recent years, the development of a WAN acceleration technology has been promoted, and a WAN acceleration device is provided in each vendor. In general, the WAN acceleration device is installed as a relay device that connects the LAN and the WAN on a client side, and the LAN and the WAN on a data center side. The WAN acceleration device controls data communicated between the client and the data center to improve the communication speed of the WAN.
In the WAN acceleration technique or the WAN acceleration devices, with the widespread use of the virtualization technique, the virtualization of the communication service including the WAN acceleration technique is being promoted. Also, a general-purpose server is used for an appliance device such as the WAN acceleration device, and technical development such as the virtualization of the device compatible with a multitenant in which the virtual environment is created in the server to aggregate the respective communication services into the same server is being promoted. In the application of the above virtualization mechanism, in order to provide a high availability at the time of failure of the communication service, a management mechanism provided in the virtualization mechanism is used.
Also, in a large-scale environment such as a data center, when the amount of resources of physical servers allocated to the individual virtual servers are set, separately, there is a possibility that a load on a manager increases in terms of the environment creation and maintenance. Under the circumstances, taking the amount of resources that can be allocated in the applied virtualization mechanism, and customer demands into account, a configuration of the virtual server provided to the data center is patterned to facilitate operational management.
As a background art of the technical field that provides the high availability in the communication service and an appliance device employing the virtualization mechanism, there are provided a technique in which when a failure occurs in a virtual machine (VM), the failure target VM automatically restarts, and a technique in which a redundant configuration including a VM that runs the communication service, and a VM of a standby system which is a switching destination at the time of failure is produced, and the system is switched to another at the time of failure (failover) so that the communication service can be continued (refer to “vSphere Availability ESXi5.5 vCenter Server 5.5”). Also, when the above redundant configuration is produced, there is a need to ensure physical resources such as a CPU and a memory with the inclusion of the standby system side in advance. Under the circumstances, there is provided a technique in which a VM of a standby system which is a switching destination at the time of failure to a plurality of VMs that run the communication service is shared so that the physical resources used by the standby system VM are deleted, and the plurality of VMs that provide the communication service are synchronized with the processing of the shared standby system VM so that the failure recovery time is reduced (refer to “Research and development projects business report to improve the accountability of cloud computing, next generation high reliability and energy-efficient IT infrastructure technology development and demonstration projects in 2011 by Ministry of Economy, Trade and Industry” in Mar. 30, 2012, page 103-108).
Also, JP-A-2005-141605 discloses a technique in which a standby state of a computer is transited by a prediction of a load state.